When crushing or grinding rock, ore, cement clinker and other hard materials, roller crushers may be used having two generally parallel rolls which rotate in opposite directions, towards each other, and which are separated by a gap. The material to be crushed is fed by gravity or choke-fed into the gap. One type of roller crusher is called high pressure grinding rollers or high pressure roller crushers. This type of roller crusher uses a crushing technique called interparticle crushing. Here, the material to be crushed or pulverised is crushed, not only by the crushing surface of the rolls, but also by particles in the material to be crushed, hence the name interparticle crushing. One example of a high pressure grinding roller is described in EP-516 952.
The rollers of the roller crusher is exposed to a very high pressure and accordingly for extreme wear from the material to be crushed. When the roller surface is worn to a certain extent, the roller must be dismounted to be reconditioned or replaced. This dismounting operation is difficult to execute at the installation place of the equipment, in most cases requiring the whole assembly formed by the shaft, crushing shell, end bearings and respective bearing housings to be removed from the equipment and transported to a place in which the reconditioning or replacement of the crushing surface and, eventually, of the bearings, can be adequately and safely carried out. The subsequent mounting is equally complicated.
Taking into account that the assembly defined by each of the rollers and respective bearings and bearing housings represents a large weight, corresponding to a preponderant part of the weight of the equipment as a whole, the operations of dismounting, carrying and remounting the roller assemblies require special cares, which are complex, time-consuming and, consequently, expensive.